DNS is a Domain Name Server.
It's basic job is to translate a URL into the correct IP address.
* A URL is a name like:
www.ozroundtable.com - something we humans can understand.
* An IP address is like: 207.210.66.212 - something computers can use to send stuff around the internet efficiently.
As you can imagine, this translating of names into IP addresses is going on continuously - it happens every time you click on a link, select a favourite or type a name into the address bar of your browser - before it communicates with the site you actually want to get to.... and it happens for every person on the internet.
This is what a Domain Name Server does.
The amount of traffic for this little exercise is huge. It is obvious that no one computer can handle the job but, even if it could, the traffic jam to get to it would be immense.... so they simply have lots of these DNS servers around, with copies of the same information. (You will have a default DNS that you will automatically be sent to for resolving IP addresses, but you can change that.)
Fortunately for DNSs,
website servers are allocated an IP address and tend to keep it for a long, long time. This is good for having lots of domain name servers scattered around the world, since it means once an entry has been received, it is good for a long while - so there is no requirement for the DNS's around the world to get frequent updates. But updates do happen ... New websites, moving a site to a new server for example.
When these changes occur, they must be sent across the whole internet to all the DNSs - and, because they are low priority, this takes time. When someone tells you it could take 24 hours for a new (or moved) website to be 'found' - this is the reason why.
One other little trick to reduce the DNS traffic is for your computer to remember the IP address, so it doesn't have to look it up over and over again. This is called your DNS cache. (sound familiar?) If it contains an 'old' IP address, then it will try sending your information to the wrong place which just won't work - so 'flushing' it cleans out all its entries and forces your computer to go to a DNS for (hopefully) the updated address.
This is where Low's suggestion is relevant ... some DNSs are better for getting more up-to-date info. The one he mentions, however, is located in San Francisco - so your DNS lookup will have to travel across the Pacific and back, before you can head for the website. So long as we don't have tens of thousands of people doing this, it's no big deal.
But, as I understand it, after the dust has settled around the server, the default DNS you are sent to should have the right address within 24 hours.
But you still need the website server to be running to actually then get into the website - and ours is still yo-yoing like the Coca-Cola demonstration team...
